Android 奇怪的错误：在外部存储器中创建文件会将资源id变为无效id

我有一些活动，其中一个创建某种序列化为文件的对象，另一个活动应该在数据目录中显示序列化对象的列表（并且有一个“创建新”按钮，用于启动创建新对象的活动）

当目录为空时，所有工作正常，没有崩溃。实际上，目录不必为空。应该显示的文件都以一个特定的扩展名结束，主应用程序会将它们过滤掉。如果我更改文件的扩展名，应用程序不会崩溃

当我创建其中一个对象时，该对象会正确地保存到

/sdcard/data/org.my.package/files/the_object_file

中，但此时，如果我打开显示序列化对象列表的活动，我会得到一个

android.content.res.Resources$NotFoundException

我还必须说，这些活动使用片段，异常发生在一段代码中，看起来像这样：

public class ShowObjectsActivity extends FragmentActivity {


    public static final int SHOW_CREATE_OBJECT_ACTIVITY = 3;

    public static final int CREATE_OBJECT = RESULT_FIRST_USER + 1;
    public static final int LOAD_OBJECT = RESULT_FIRST_USER + 2;

    public static final String THE_OBJECT = "org.my.package.THE_OBJECT";

    private MainObjectsFragment mainFragment = null;

    private String[] objectNames = null;
    private ObjectSerializer serializer = null;


    @Override
    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.objects);

        if (mainFragment == null) {
            mainFragment = new MainObjectsFragment();

            // Fails on the following .add
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.objects_fragment_container, mainFragment).commit();
        }

        Intent intent = getIntent();
        serializer = new ObjectSerializer(
                intent.getStringExtra(TheMainActivity.APP_FILES_DIRECTORY));
        this.objectNames = intent.getStringArrayExtra(
                TheMainActivity.OBJECTS_NAMES);
        if (this.objectNames == null) {
            this.objectNames = new String[0];
        }

    }

    @Override
    public void onStart() {

        super.onStart();
        // Set the ArrayAdapter for the ListView
        mainFragment.setObjectsAdapter(this,
                                       this.objectNames);
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent intent) {
        if (requestCode == SHOW_CREATE_OBJECT_ACTIVITY) {
            if (resultCode == RESULT_OK) {
                setResult(CREATE_OBJECT, intent);
                finish();
            }
        }
    }

    public void createNewObject(View view) {

        Intent intent = new Intent(this, NewObjectActivity.class);
        startActivityForResult(intent, SHOW_CREATE_OBJECT_ACTIVITY);
    }


}

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:id="@+id/objects_fragment_container"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent" />

objects.xml

布局文件如下：

public class ShowObjectsActivity extends FragmentActivity {


    public static final int SHOW_CREATE_OBJECT_ACTIVITY = 3;

    public static final int CREATE_OBJECT = RESULT_FIRST_USER + 1;
    public static final int LOAD_OBJECT = RESULT_FIRST_USER + 2;

    public static final String THE_OBJECT = "org.my.package.THE_OBJECT";

    private MainObjectsFragment mainFragment = null;

    private String[] objectNames = null;
    private ObjectSerializer serializer = null;


    @Override
    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.objects);

        if (mainFragment == null) {
            mainFragment = new MainObjectsFragment();

            // Fails on the following .add
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.objects_fragment_container, mainFragment).commit();
        }

        Intent intent = getIntent();
        serializer = new ObjectSerializer(
                intent.getStringExtra(TheMainActivity.APP_FILES_DIRECTORY));
        this.objectNames = intent.getStringArrayExtra(
                TheMainActivity.OBJECTS_NAMES);
        if (this.objectNames == null) {
            this.objectNames = new String[0];
        }

    }

    @Override
    public void onStart() {

        super.onStart();
        // Set the ArrayAdapter for the ListView
        mainFragment.setObjectsAdapter(this,
                                       this.objectNames);
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent intent) {
        if (requestCode == SHOW_CREATE_OBJECT_ACTIVITY) {
            if (resultCode == RESULT_OK) {
                setResult(CREATE_OBJECT, intent);
                finish();
            }
        }
    }

    public void createNewObject(View view) {

        Intent intent = new Intent(this, NewObjectActivity.class);
        startActivityForResult(intent, SHOW_CREATE_OBJECT_ACTIVITY);
    }


}

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:id="@+id/objects_fragment_container"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent" />

请注意，

MainObjectsFragment

onCreateView

不执行任何与名称数组相关的操作。另外，

ShowObjectsActivity

中的崩溃发生在根本没有触及意图之前

以下是回溯：

E/AndroidRuntime( 1186): FATAL EXCEPTION: main
E/AndroidRuntime( 1186): android.content.res.Resources$NotFoundException: Resource ID #0x7f050002 type #0x12 is not valid
E/AndroidRuntime( 1186):        at android.content.res.Resources.loadXmlResourceParser(Resources.java:2297)
E/AndroidRuntime( 1186):        at android.content.res.Resources.getLayout(Resources.java:988)
E/AndroidRuntime( 1186):        at android.view.LayoutInflater.inflate(LayoutInflater.java:349)
E/AndroidRuntime( 1186):        at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:363)
E/AndroidRuntime( 1186):        at android.widget.ArrayAdapter.getView(ArrayAdapter.java:354)
E/AndroidRuntime( 1186):        at android.widget.AbsListView.obtainView(AbsListView.java:1523)
E/AndroidRuntime( 1186):        at android.widget.ListView.makeAndAddView(ListView.java:1786)
E/AndroidRuntime( 1186):        at android.widget.ListView.fillDown(ListView.java:705)
E/AndroidRuntime( 1186):        at android.widget.ListView.fillFromTop(ListView.java:762)
E/AndroidRuntime( 1186):        at android.widget.ListView.layoutChildren(ListView.java:1639)
E/AndroidRuntime( 1186):        at android.widget.AbsListView.onLayout(AbsListView.java:1318)
E/AndroidRuntime( 1186):        at android.view.View.layout(View.java:7243)
E/AndroidRuntime( 1186):        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1285)
E/AndroidRuntime( 1186):        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1161)
E/AndroidRuntime( 1186):        at android.widget.LinearLayout.onLayout(LinearLayout.java:1078)
E/AndroidRuntime( 1186):        at android.view.View.layout(View.java:7243)
E/AndroidRuntime( 1186):        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1285)
E/AndroidRuntime( 1186):        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1161)
E/AndroidRuntime( 1186):        at android.widget.LinearLayout.onLayout(LinearLayout.java:1078)
E/AndroidRuntime( 1186):        at android.view.View.layout(View.java:7243)
E/AndroidRuntime( 1186):        at android.widget.FrameLayout.onLayout(FrameLayout.java:369)
E/AndroidRuntime( 1186):        at android.view.View.layout(View.java:7243)
E/AndroidRuntime( 1186):        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1285)
E/AndroidRuntime( 1186):        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1161)
E/AndroidRuntime( 1186):        at android.widget.LinearLayout.onLayout(LinearLayout.java:1078)
E/AndroidRuntime( 1186):        at android.view.View.layout(View.java:7243)
E/AndroidRuntime( 1186):        at android.widget.FrameLayout.onLayout(FrameLayout.java:369)
E/AndroidRuntime( 1186):        at android.view.View.layout(View.java:7243)
E/AndroidRuntime( 1186):        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1285)
E/AndroidRuntime( 1186):        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1161)
E/AndroidRuntime( 1186):        at android.widget.LinearLayout.onLayout(LinearLayout.java:1078)
E/AndroidRuntime( 1186):        at android.view.View.layout(View.java:7243)
E/AndroidRuntime( 1186):        at android.widget.FrameLayout.onLayout(FrameLayout.java:369)
E/AndroidRuntime( 1186):        at android.view.View.layout(View.java:7243)
E/AndroidRuntime( 1186):        at android.view.ViewRoot.performTraversals(ViewRoot.java:1181)
E/AndroidRuntime( 1186):        at android.view.ViewRoot.handleMessage(ViewRoot.java:1906)
E/AndroidRuntime( 1186):        at android.os.Handler.dispatchMessage(Handler.java:130)
E/AndroidRuntime( 1186):        at android.os.Looper.loop(SourceFile:351)
E/AndroidRuntime( 1186):        at android.app.ActivityThread.main(ActivityThread.java:4070)
E/AndroidRuntime( 1186):        at java.lang.reflect.Method.invokeNative(Native Method)
E/AndroidRuntime( 1186):        at java.lang.reflect.Method.invoke(Method.java:538)
E/AndroidRuntime( 1186):        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:906)
E/AndroidRuntime( 1186):        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:664)
E/AndroidRuntime( 1186):        at dalvik.system.NativeStart.main(Native Method)
W/ActivityManager(  197):   Force finishing activity org.my.package/.ShowObjectsActivity
W/ActivityManager(  197):   Force finishing activity org.my.package/.TheMainActivity

我做错什么了吗？为什么数据目录中存在文件会导致

ResourceNotFound

错误

---

编辑：我想我开始了解错误是如何发生的。

MainObjectsFragment

的布局包含一个

ListView

。我提供了一个

TextView

来显示视图是否为空，xml如下所示：

public void showObjectsActivity(View view) {

    if (!isExternalStorageAvailable()) {
        AlertDialog.Builder dialog = new AlertDialog.Builder(this);
        dialog.setTitle(R.string.external_storage_not_available_title);
        dialog.setMessage(R.string.external_storage_not_available_msg);
        dialog.setNeutralButton(R.string.close, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                // Empty
            }
        });

        dialog.create().show();
    } else {
        Intent intent = new Intent(this, ShowObjectsActivity.class);
        String app_files_directory = getTheFilesDir();
        // When the file is in the directory the following is the array I'd expect.
        // an array with the names of the objects
        intent.putExtra(OBJECTS_NAMES,
                        new ObjectSerializer(
                                app_files_directory).listObjectNames());
        intent.putExtra(APP_FILES_DIRECTORY, app_files_directory);

        startActivityForResult(intent, SHOW_OBJECTS);
    }
}

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">

    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="0.5">

        <ListView
            android:id="@+id/main_objects_view"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent" />

        <TextView
            android:id="@android:id/empty"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:text="@string/no_objects_available"
            android:textSize="22sp"
            android:gravity="center" />
    </LinearLayout>

    <Button
        android:id="@+id/new_object_button"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/new_object"
        android:textSize="18sp"
        android:onClick="createNewObject" />

</LinearLayout>

---

我得说它在梅因。您还可以在R.java中查看什么是#0x7f050002。@njzk2我更新了我的问题。如果是listfragment，则需要在it@njzk2我从来没有提到过

列表片段，所以它不是。它是一个普通的
片段
，其中有一个
列表视图
。当我有时间时，我会尝试使用
ListFragment
，但我还是想理解这个错误。我假设布局中存在@android:id/empty